Nomad REST API Drain Deadline

Nomad
1

Is there a way to drain a node via the REST API but disable the drain deadline similar to how the Nomad CLI works?

With the CLI no-deadline can be specified:

I have a migrate stanza configured but an unknown number of jobs on that node. I’d have to ballpark the migrate time for each job to all fit under the deadline so if I could ignore that that would help a lot.

Eyeballing the CLI doc I took a pass at similar naming in the REST version but this doesn’t seem to be documented anywhere. Got a 200 back:

{ "DrainSpec": { "NoDeadline": True, "IgnoreSystemJobs": True } }

Is this a supported configuration or does the documentation just need updating?

2

Looking at the code that gets executed (https://github.com/hashicorp/nomad/blob/master/api/nodes.go#L80), in snippet form below, it seems that the API expects a duration instead of a NoDeadline boolean. Maybe try to set the Deadline field to 0 (the CLI sets the value to 0 when “noDeadline” is specified).

// Parse the duration
var d time.Duration
if force {
	d = -1 * time.Second
} else if noDeadline {
	d = 0
}

// DrainSpec describes a Node's drain behavior.
type DrainSpec struct {
	// Deadline is the duration after StartTime when the remaining
	// allocations on a draining Node should be told to stop.
	Deadline time.Duration

	// IgnoreSystemJobs allows systems jobs to remain on the node even though it
	// has been marked for draining.
	IgnoreSystemJobs bool
}

// UpdateDrain is used to update the drain strategy for a given node. If
// markEligible is true and the drain is being removed, the node will be marked
// as having its scheduling being eligible
func (n *Nodes) UpdateDrain(nodeID string, spec *DrainSpec, markEligible bool, q *WriteOptions) (*NodeDrainUpdateResponse, error) {
	req := &NodeUpdateDrainRequest{
		NodeID:       nodeID,
		DrainSpec:    spec,
		MarkEligible: markEligible,
	}

	var resp NodeDrainUpdateResponse
	wm, err := n.client.write("/v1/node/"+nodeID+"/drain", req, &resp, q)
	if err != nil {
		return nil, err
	}
	resp.WriteMeta = *wm
	return &resp, nil
}
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